Coating compositions containing highly structured macromolecules

ABSTRACT

The invention is directed to a two-pack high solids low VOC ambient curable coating composition, which includes cross linking and binder components. The crosslinking component includes a polyamine, a polyketimine, or a combination thereof. The polyamine is provided on an average with at least two amine functionalities per polymer chain and the polyketimine is provided on an average with at least two ketimine functionalities per polymer chain. A reactive diluent in the binder component includes a macromolecule substantially free from acrylate functionalities and having at least two acetoacetate functionalities per the macromolecule. If desired, the coating composition includes a binder polymer. The coating composition of the invention is particularly suited in automotive refinish coatings.

This application is a §371 of PCT/US00/11794 filed on May 2, 2000, whichclaims the benefit of U.S. Provisional Application 60/132,624 filed onMay 5, 1999.

BACKGROUND OF THE INVENTION

The present invention relates to curable compositions and moreparticularly to low VOC (volatile organic component) ambient temperaturecurable coating compositions suitable for use in automotive refinishapplications. A number of clear and pigmented coating compositions areutilized in various coatings, such as, for example, primers, basecoatsand clearcoats used in automotive refinish coatings, which are generallysolvent based.

In repairing damage, such as dents and scratches to autobodies, theoriginal coating in and around the damaged area is typically sanded orground out by mechanical means. Some times the original coating isstripped off from a portion or off the entire autobody to expose thesubstrate (e.g., bare metal) underneath. After repairing the damage, therepaired surface is coated, preferably with low VOC coatingcompositions, typically in portable or permanent low cost paintingenclosures vented to the atmosphere to remove the organic solvents fromthe freshly applied paint coatings in an environmentally safe manner.Generally, the drying and curing of the freshly applied paint takesplace within these enclosures. Furthermore, it is preferable to conductthe foregoing drying and curing steps within the enclosure to preventthe wet paint from collecting dirt in the air or other contaminants.

As these paint enclosures take up significant floor space of typicalsmall autobody paint repair shops, these shops prefer to dry and curethese paints as rapidly as possible. More expensive enclosures arefrequently provided with heat sources, such as conventional heat orinfrared lamps located inside the enclosure to cure the freshly appliedpaint at accelerated rates. Therefore, to provide more cost effectiveutilization of shop floor space and to minimize fire hazards resultingfrom wet coatings from solvent based coating compositions, there existsa continuing need for low VOC fast curing coating formulations whichcure under ambient conditions while still providing outstandingperformance characteristics such as solvent resistance

One of the approaches used in addressing the foregoing involvesutilizing a binder system that contains a conventional polyester resinfunctionalized with acetoacetate groups and having at least two acrylatemoieties. However, the use of acrylate functionalities, such as thosedisclosed in U.S. Pat. No. 5,288,802, is not the best approach, if rapidcure coatings are desired. Thus, a continuing need still exists for alow VOC coating composition that cures rapidly under ambient conditions.

Another disadvantage of the compositions described in U.S. Pat. No.5,288,802 is the disagreeable and offensive odor associated withacrylate functionalized diluents used in these compositions.

Thus, it would be most advantageous to provide a composition that notonly cures more rapidly than current undercoatings of this type topermit autobody paint repair shops to rapidly complete the repairs, butalso has less offensive odors.

STATEMENT OF THE INVENTION

The present invention is directed to a coating composition comprising:

a crosslinking component comprising a polyamine, a polyketimine, or acombination thereof, wherein said polyamine has an average of at leasttwo amine functionalities per polyamine molecule and wherein saidpolyketimine has an average of at least two ketiniine functionalitiesper polyketimine molecule; and

a binder component comprising:

at least one structured reactive diluent having a GPC weight averagemolecular weight in the range of from 100 to 45,000, said diluent beingsubstantially free from acrylate functionalities and having at least twoacetoacetate functionalities per diluent molecule.

The present invention is further directed to a method of producing acoating on a substrate, said method comprising:

mixing a crosslinking component with a binder component to form a potmix, said crosslinking component comprising a polyamine, a polyketimine,or a combination thereof, said polyamine having an average of at leasttwo amine functionalities per polyamine molecule and said polyketiminehaving an average of at least two ketimine functionalities perpolyketimine molecule; said binder component comprising at least onestructured reactive diluent having a GPC weight average molecular weightin the range of from 100 to 45,000, said diluent being substantiallyfree from acrylate functionalities and having at least two acetoacetatefunctionalities per said diluent molecule;

applying a layer of said pot mix on said surface; and

curing said layer under ambient conditions to form said coating on saidsurface of said substrate.

One of the advantages of the present invention is its low VOC, which issignificantly below the current guidelines of Environment ProtectionAgency (EPA) of the United States.

Another advantage of the composition of the present invention is that itis free from isocyanate groups. As a result, it has less toxicity thanconventional isocyanate group-containing coating compositions, such aspolyurethanes. This reduced toxicity is particularly helpful for autopaint repair shops that may not have physical facilities required tohandle more toxic compositions containing isocyanate functionalities.

Yet another advantage of the composition of the present invention isthat it reduces the time-to-sand, before the coating can be sandedwithout fouling the sandpaper, thereby increasing the number of repairsthat could be performed in a day.

Still another advantage of the composition of the present invention isthat it does not release pungent odors often associated with lowmolecular weight compounds containing acrylate functional moieties.Compounds such as these are employed in conventional low VOCnon-isocyanate containing coating compositions.

DETAILED DESCRIPTION OF THE INVENTION

As used herein:

“Two-pack coating composition” means a thermosetting compositioncomprising two components that are stored in separate containers, whichare typically sealed for increasing the shelf life of the components ofthe coating composition. The components are mixed just prior to use toform a pot mix, which has a limited pot life, typically a few minutes,such as 15 minutes to 45 minutes to a few hours, such as 2 hours to 6hours. The pot mix is applied as a layer of desired thickness on asubstrate surface, such as an autobody. After application, the layerdries and cures to form a coating on the substrate surface havingdesired coating properties, such as solvent resistance.

“Low VOC coating composition” means a coating composition that is lessthan about 0.6 kilogram of organic solvent per liter (5 pounds pergallon) of the composition, as determined under the procedure providedin ASTM D3960.

“High solids composition” means a coating composition having a solidscomponent of above 30 percent, preferably in the range of from 40 to 95percent and more preferably in the range of from 45 to 80 percent, allin weight percentages based on the total weight of the composition.

“GPC weight average molecular weight” means a weight average molecularweight measured by utilizing gel permeation chromatography. A highperformance liquid chromatograph (HPLC) supplied by Hewlett-Packard,Palo Alto, Calif. was used. Unless stated otherwise, the liquid phaseused was tetrahydrofurane and the standard was polymethyl methacrylate.

“Polydispersity” means GPC weight average molecular weight divided byGPC number average molecular weight.

“Polymer solids” or “Binder solids” means a polymer or binder in its drystate.

“(Meth)acrylate” means acrylate and methacrylate.

“Structured reactive diluent” means a structured molecule, such as amacromolecule, oligomer or polymer, which unlike conventional resins,has a very well defined structure. Examples of these diluents includestar, expanded star, dendritic (hyper branched), or cyclodextricstructured molecules.

One efficient approach to reduce VOC is to use high solids coatingcompositions containing low weight average molecular weight, i.e., lessthan about 10,000, structured reactive diluents functionalized withstrategically positioned acetoacetate functional groups. This also hasthe benefit of significantly increased reactivity and reduced odorrelative to acrylate functionalized diluents.

The present invention is directed to a coating composition suited forvarious coating processes, particularly in automotive refinishingprocess used for coating autobodies. The composition is a two-packcomposition, which includes a crosslinking component and a bindercomponent. The coating composition includes in the range of from 20percent to 80 percent, preferably in the range of from 30 percent to 70percent and more preferably in the range of from 40 percent to 65percent of the crosslinking component, the percentages being in weightpercentages based on the total weight of binder and crosslinkingcomponents solids.

The crosslinking component includes a polyamine, a polyketimine, or acombination thereof. Polyketimine is preferred. When used as acombination of a polyamine and a polyketimine, the ratio thereof byweight parts is in the range from 1 to 100 through 100 to 1, preferablyin the range of from 1 to 50, more preferably in the range of from 1 to20.

The polyamine has a weight average molecular weight of at least 100, asdetermined by gel permeation chromatography using polymethylmethacrylate standards. Typically, the GPC weight average molecularweight ranges from about 100 to about 50,000, preferably from about 150to about 10,000 and more preferably from about 200 to about 5,000.

The polyamine has an average of at least two amine functionalities permolecule, which may be primary, secondary or a combination of secondaryand primary amine functionalities. Preferably, the polyamine has anaverage of from about 2 to about 25 and more preferably, in the range offrom about 2 to about 6 amine functionalities per polyamine molecule.These amine functionalities may be present either as pendantfunctionalities or amine functionalities positioned in the backbone ofthe polymer chain. Pendent amine functionalities are preferred.

Examples of representative polyamines suitable for use in the inventioninclude aliphatic or cycloaliphatic amines, or a combination thereof Thealiphatic polyamine is preferred.

Examples of suitable polyamines include primary and secondary amines,such as, ethylenediamine, propylenediamine, butylenediamine,pentamethylenediamine, hexamethylenediamine, decamethylenediamine,4,7-dioxadecane-1,10-diamine, dodecamethylenediamine,4,9-dioxadodecane-1,12-diamine,7-methyl-4,10-dioxatridecane-1,13-diamine, 1,2-diaminocyclohexane,1,4-diaminocyclohexane, 4,4′-diminodicyclohexyl methane, isophoronediamine, bis(3-methyl-4-aminocyclohexyl)methane,2,2-bis(4-aminocyclohexyl)propane, nitrile tris(ethane amine),bis(3-aminopropyl) methylamine, 3-amino-1-(methylamino)propane,³-amino-1-(cyclohexylamino)propane, and N-(2-hydroxyethyl)ethylenediamine. Ethylenediamine, propylenediamine, butylenediamine and1,2-diaminocyclohexane are preferred.

Other suitable polyamines include those of the formula:

H₂N—(R₂)_(n)—NH—(R₁)_(n)—NH₂,

where the R₁ and R₂ groups may be the same or different and represent analkylene group containing 2 to 6 and preferably 2 to 4 carbon atoms andn is an independently selected number in the range of from 1 to 6 andpreferably in the range of from 1 to 3. The alkylene group is acycloalkylene group or an alkylene group containing an ether-oxygenatom. Examples of representative polyamines containing polyalkylenegroups include diethylene triamine, dipropylene triamine and dibutylenetriamine. It is preferred that these polyamines should be of acycloaliphatic nature and contain 5 to 15 carbon atoms, such asisophoronediamine; more particularly containing an alpha-aklyl group,such as bis(3-methyl-4-aminocyclohexyl)methane andbis(3-methyl-4-aminocyclohexyl)propane.

Other suitable polyamines include reaction products of primary orsecondary polyamines, such as ethylene diamine and diethylene triamine,with adducts of polyhydroxyls reacted with polyepoxides, polyacrylates,polymethacrylates, polyisocyanates, polyoxides or a combination thereof.

Suitable polyhydroxyls include ethylene glycol, propylene glycol,diethylene glycol, tetramethylene diol, neopentyl glycol, hexamethylenediol, cyclohexane diol, 4,4′-dihydroxybenzophenone,bis-(4-hydroxycyclohexane)methane, glycerol, trimethylol ethane,trimethylol propane, polyvinyl phenol and pentaerythritol.

Some of the suitable polyepoxides include those containing at least twooxirane groups in the molecule, i.e.,

where n is at least two, R₁ is hydrogen or methyl, and R₂ broadlyrepresents an organic based molecule or polymer typically composed ofcarbon, hydrogen, oxygen, and optionally nitrogen, sulfur, or both.Hydroxyl substituent groups may also be present, as well as halogen andether groups. Generally, the epoxide equivalent weight ranges from about100 to about 1500, preferably from about 100 to about 1200, and morepreferably from about 150 to about 600. These polyepoxides can bebroadly categorized as being aliphatic, aromatic, cyclic, acyclic,alicyclic or heterocyclic.

Another group of useful polyepoxides for use in the present inventionincludes epoxy novalac resins. These resins are prepared by reacting anepihalohydrin with the condensation product of an aldehyde with amonohydric or polyhydric phenol. One example is the reaction product ofepichlorohydrin with a phenolformaldehyde condensate.

Another particularly preferred group of the polyepoxides are thepolyglycidyl ethers of polyhydric aromatic hydroxy compounds, such asfor example, dihydric phenols. The phenol must be at least dihydric,such as, for example, resorcinol, catechol, hydroquinone,bis(4-hydroxyphenyl)-1,1-isobutane; 4,4-dihydroxybenzophenone;bis(4-hydroxyphenyl)-1,1-isobutane; 4,4-dihydroxybenzophenone;bis(4-hydroxyphenyl)-1,1-ethane; bis(2-hydroxynaphenyl)methane;1,5-hydroxynaphthalene and 4,4′-isopropylidenediphenol, i.e., bisphenolA. Preferably bisphenol A is utilized. Of the many polyepoxidespossible, the one principally utilized is epichlorohydrin althoughepibromohydrin is also quite useful. The polyglycidyl ethers especiallyuseful herein are obtained by reacting epichlorohydrin and bisphenol Ain the presence of an alkali, such as sodium or potassium hydroxide. Theseries of epoxy resins sold by Shell Chemical Company under thetrademark EPON are especially useful herein.

Another group of useful polyepoxides are the polyglycidyl ethers derivedfrom reacting epihalohydrin, preferably epichlorohydrin, with polyhydricalcohols, such as ethylene glycol; diethylene glycol; triethyleneglycol; 1,2-propylene glycol; 1,4-butylene glycol; 1,5-pentanediol;1,2,6-hexanetriol; glycerol and trimethylolpropane.

Also useful are the polyepoxides which are polyglycidyl ethers ofpolycarboxylic acids. These materials are produced by the reaction of anepoxy compound, such as epichlorohydrin with an aliphatic or aromaticpolycarboxylic acid such as oxalic acid; succinic acid; glutaric acid;terephthalic acid; 2,6-naphthalene dicarboxylic acid and dimerizedlinoleic acid.

Still another group of polyepoxides are derived from epoxidation ofolefinically unsaturated alicyclic materials. Among these are the epoxyalicyclic ethers and esters, which are well known in the art.

It should be understood that mixtures of the polyepoxides are alsouseful herein. The preferred epoxy equivalent weight of thepolyepoxide(s) is in the range of from 87 to 6000, more particularly therange of from 120 to 1000. Suitable polyoxides include those containingoxyalkylene groups, i.e.,

wherein R is hydrogen or C₁ to C₆ alkyl, m is an integer varying from 1to 4 and n is an integer varying from 2 to 50. The proportion ofoxyalkylene groups in the polyepoxide depends upon a number of factors,among them the size of the oxyalkylene group and the nature of thepolyepoxide.

Examples of suitable polyisocyanates include aliphatic, cycloaliphaticor aromatic di-, tri- or tetraisocyanates which may or may not beethylenically unsaturated, such as 1,2-propylene diisocyanate,trimethylene diisocyanate, tetramethylene diisocyanate, 2,3-butylenediisocyanate, hexamethylene diisocyanate, octamethylene diisocyanate,2,2,4-trimethyl hexamethylene diisocyanate, 2,4,4-trimethylhexamethylene diisocyanate, dodecamethylene diisocyanate, omega,omega-dipropyl ether diisocyanate, 1,3-cyclopentane diisocyanate,1,2-cyclohexane diisocyanate, 1,4-cyclohexane diisocyanate, isophoronediisocyanate, 4-methyl-1,3-diisocyanatocyclohexane, trans-vinylidenediisocyanate, dicyclohexylmethane4,4′-diisocyanate,3,3′-dimethyl-dicyclohexylmethane4,4′-diisocyanate, a toluenediisocyanate, 1,3-bis(1-isocyanato1-methylethyl)benzene,1,4-bis(1-isocyanato-1-methylethyl)benzene,1,3-bis(isocyanatomethyl)benzene a xylene diisocyanate,1,5-dimethyl-2,4-bis(isocyanatomethyl)benzene,1,5-dimethyl-2,4-bis(2-isocyanatoethyl)benzene,1,3,5-triethyl-2,4-bis(isocyanatomethyl)benzene,4,4′-diisocyanatodiphenyl, 3,3′-dichloro-4,4′-diisocyanatodiphenyl,3,3′-diphenyl-4,4′-diisocyanatodiphenyl,3,3′-dimethoxy-4,4′-diisocyanatodiphenyl,4,4′-diisocyanatodiphenylmethane,3,3′-dimethyl-4,4′-diisocyanatodiphenyl methane, adiisocyanatonaphthalene, polyisocyanates having isocyanaurate structuralunits, the adduct of 2 molecules of a diisocyanate, such ashexamethylene diisocyanate or isophorone diisocyanate, and a diol suchas ethylene glycol, the adduct of 3 molecules of hexamethylenediisocyanate and 1 molecule of water (available under the trademarkDesmodur® N from Bayer Corporation of Pittsburgh, Pa.), the adduct of 1molecule of trimethylol propane and 3 molecules of toluene diisocyanate(available under the trademark Desmodur® L from Bayer Corporation ), theadduct of 1 molecule of trimethylol propane and 3 molecules ofisophorone diisocyanate, compounds such as 1,3,5-triisocyanato benzeneand 2,4,6-triisocyanatotoluene, and the adduct of 1 molecule ofpentaerythritol and 4 molecules of toluene diisocyanate.

Examples of suitable polyacrylates or polymethacrylates includepolymerized monomers, such as acrylic or methacrylic esters of a mono-,di- or polyfunctional hydroxyl compound including methyl acrylate,methyl methacrylate, ethyl acrylate, hydroxyethyl acrylate, hydroxyethylmethacrylate, propyl acrylate, hydroxypropyl methacrylate, butylacrylate, butyl methacrylate, hydroxyhexyl acrylate, 2-ethylhexylacrylate, octyl acrylate, isobomyl acrylate, oleyl acrylate, glycidylmethacrylate or (meth)acryloxypropyl trimethoxysilane.

The polyketimines which are suitable for use in the present inventionare obtained by blocking the amino groups on the aforedescribedpolyamines with a blocking agent, such as an aldehyde or ketone havingnot more than 18 carbon atoms, preferably 3 to 10 carbon atoms. Examplesof suitable blocking agents for the amino groups include acetone,diethyl ketone, methylisobutyl ketone, isobutyraldehyde,hydroxybutyraldehyde, pentanone, cyclohexanone, ethylamyl ketone,hydroxycitronellal, isophorone and decanone. An aliphatic orcycloaliphatic ketone is preferred and an aliphatic or cycloaliphaticketone with 3 to 8 carbon atoms is more preferred.

The binder component of the coating composition includes in the range offrom percent 1 percent to 90 percent, preferably in the range of from 5percent to 80 percent and more preferably in the range of from 20percent to 60 percent of at least one structured reactive diluent, thepercentages being in weight percentages based on the total weight ofbinder solids. The structured reactive diluent molecule which issubstantially free from acrylate functionalities and has at least 2,preferably in the range of from 2 to 30, more preferably in the range of2 to 25 and still more preferably in the range of 2 to 10 and mostpreferably in the range of acetoacetate groups. The structured reactivediluent has a GPC weight average molecular weight in the range of from100 to 45,000, preferably in the range of from 200 to 10,000 and morepreferably in the range of from 400 to 5,000. The structured reactivediluent has an acetoacetate equivalent weight (grams/equivalent) fromabout 100 to about 1000, preferably from about 100 to about 800 and morepreferably from about 100 to about 600. The structured reactive diluenthas a Tg in the range of from −100° C. to 100° C., preferably in therange of from −80° C. to 50° C. and more preferably in the range of from−70° C. to −30° C.

The “highly ordered” structure of these structured reactive diluentsmake them dramatically different from conventional polyacrylic orpolyester oligomers, which are linear or linear with random branching.

Some of the suitable structured reactive diluents include those producedby reacting a ketene or an acetoacetate compound, such astert-butylacetoacetate, with a polyol such as,1,4-cyclohexanedimethanol, ethylene glycol, glycerine, neopentyl glycol,bisphenol A extended with ethylene oxide, trimethylol propane,tris(2-hydroxyethyl)isocyanurate (Theic), caprolactone extendedtris(2-hydroxyethyl)isocyanurate, pentaerthyritol, the hexafunctionalhydroxyl compound prepared from the bisepoxide Epon® 828 (Bisphenol Aand epichlorohydrin) and diethanol amine. The structured reactivediluents may also be prepared by reacting a ketene or an acetoacetatecompound, such as tert-butylacetoacetate, with a reaction product of anoligomeric acid, such as dimethylolpropionic acid with a monofunctionalepoxide, such as ethylene oxide or a lactone, such as ε-caprolactone.The foregoing structured diluents typically have a star shaped structurehaving at least 2 arms, preferably 3 to 10 arms. The process forproducing the foregoing structural reactive diluents is shown below:

The branches on the star shaped structure described above may beexpanded by providing intervening functionalities, which are terminatedwith hydroxyl functionalities. These terminal hydroxyl functionalitieson the star shaped polyols are then reacted with a ketene ortert-butylacetoacetate to provide the structured reactive diluent withthe acetoacetate functionalities.

The intervening functionalities on the star shaped polyol describedabove are provided by an acid anhydride, followed by reaction with anepoxide or a lactone having 5 to 20 carbon atoms, more particularlyε-caprolactone. The formulas below describe some of the details of thesereactions:

Suitable acid anhydrides include succinic anhydride, maleic anhydride,phthalic anhydride, hexahydrophthalic anhydride, methylhexahydrophthalic anhydride, (MHHPA), trimellitic anhydride,hydrogenated trimellitic anhydride, the Diels-Alder adduct of maleicanhydride with sorbic acid, and the hydrogenated Diels-Alder adduct ofmaleic anhydride with sorbic acid. Suitable epoxides include ethyleneoxide and monoepoxyesters such as, epoxyesters of benzoic acid, aceticacid, privalic acid (Cardura™ E5), and versatic acid (Cardura™ E4). Whena caprolactone is utilized, its percentage should not exceed more than50 percent by weight, otherwise the resultant coating therefrom becomestoo soft. The resulting primary or secondary hydroxyl groups generatedby the aforedescribed syntheses are subsequently reacted with anacetoacetate compound, such as tert-butyl acetoacetate, to providecompounds that are capped with acetoacetate moieties. Additionalinformation about the hydroxyl analogues and their unique structures isdisclosed in the U.S. Pat. No. 5,753,756 to Aerts et al. and in StarOligomers for low VOC Polyurethane Coatings by Huybrechts et al., inSurface Coatings International, No. 3, 1998, all of which areincorporated herein by reference.

A structured reactive diluent having expanded convergent or divergentstructures may be produced by converging over a simple core provided bythe aforedescribed polyols with additional functionalities which areterminated with acetoacetate functionalities or by diverging from asimple core provided by the aforedescribed polyols with additionalfunctionalities which are terminated with acetoacetate functionalities.

Thus, these highly structured reactive diluents possess threedistinguishing architectural features: a core, interior layers composedof repeating units attached to the core, and an exterior or terminalacetoacetate functionalities attached to the outermost generation. Theoutermost hydroxyl functionalities are functionalized with theacetoacetate functionalities to form a structured reactive diluenthaving an expanded core. The following formulas describe the structuraldetails of these reactive diluents having expanded convergent ordivergent structures:

Unlike conventional polyesters or polyester oligomers, theseexpanded-core structured reactive diluent possess a dense, compactstructure from many short branches below entanglement molecular weightand therefore, relative to conventional materials these types ofstructures exhibit reduced viscosity because they are essentiallyentanglement free. Additional details of these reactive diluents areprovided by Hult et al, in Hyperbranched Aliphatic Polyesters, PolymericMaterials Encyclopedia, Vol. 5, at page 3171, published by CRC Press,Inc. in 1996; and also by Turner et al. in, Hyperbranched Polymers,Polymer News, Vol. 22 at page 197, both of which are incorporated hereinby reference.

Still another suitable structured reactive diluent includes dendriticoligomers or polymers having hydroxyl termini that are capped withacetoacetate to form the reactive diluent. These dendritic oligomers orpolymers are polymerized from AB_(x) monomers, wherein A is ahydrocarbyl radical containing a carboxyl acid (—CO₂H), carboxyl estergroup (—CO₂R), or mixture thereof, wherein R is C₁₋₁₂ alky; B is ahydrocarbyl radical containing 1 to 10, prefeably 2 to 3, hydroxyl (—OH)or ester group (—O₂CR′), wherein R′ is C₁₋₁₂ alkyl; and x is in therange of 2 to 10, preferably in the range of 2 to 3. The resultingoligomer or polymer contains one unreacted A functional group and(x−1)_(n+1) number of unreacted B functional end groups, wherein n isthe degree of polymerization, which varies from 2 to 1000, preferably 2to 100. The dendritic oligomers or polymers can be additionally modifiedby copolymerization with the comonomers, such as lactones,hydroxycarboxylic acids, lactams, aminoacids, cyclic ethers and monomersof the general formula R″—Z_(m), where R″ is C₁₋₂₀₀ hydrocarbyl, Z ishydroxyl, amine, epoxy or carboxyl and m varies from 1 to 10, preferably2 to 6. Examples of suitable comonomers of the general formula R″—Z_(m)include dimethylolpropionic acid, caprolactone, caprolactam,pentaerythritol, glycerine, neopentyl glycol, trimethylol propane,cyclodextrine, cyclohexanedimethanol, sorbitol, and hydrogenatedbisphenol A. The structured reactive diluent formed by this process isshown below:

The foregoing materials also exhibit dramatically reduced intermolecularentanglement relative to conventional polyesters.

Still another suitable structured reactive diluent includes torus-shapedstructured compounds resulting from α-, β- or γ-cyclodextin. Cyclodextin(cycloamyloses) are torus-shaped cyclic oligosaccharides containing six,seven eight or more α-1,4-linked (+)-D-glucopyranose units. Thesederivatives are produced enzymatically from starch and are used on anindustrial scale. β-Cyclodextrin comprised of seven repeat units, hasseven primary and 14 secondary hydroxyl groups located externally on thering system. The figures shown below show such structures:

The hydroxyl groups on these cyclodextrins are reacted with anacetoacetate compound to produce the torus-shaped structured reactivediluent. The incorporation of the cyclodextrin framework intocross-linked networks imparts desired physical and chemical propertiesto the coatings resulting therefrom. Additional information is providedby M. L. Bender et al. In “Cyclodextrin Chemistry,” Springer-Verlag;Berlin, 1978, which is incorporated herein by reference. Additionalinformation on properties of cyclodextrin is also provided in theJournal of Chemical Reviews, volume 98(5), 1998, which is incorporatedherein by reference.

If desired, the binder component of the coating composition of thepresent invention further includes at least one polymer binder selectedfrom the group consisting of acrylic polymer, polyester, or acombination thereof. An acetoacetate containing acrylic polymer, anacetoacetate containing polyester or a combination thereof is preferredand the acetoacetate containing polyester is more preferred. The coatingcomposition may include in the range of from 1 percent to 75 percent,preferably in the range of from 5 percent to 55 percent and morepreferably in the range of from 10 percent to 40 percent of the binderpolymer, the percentages being in weight percentages based on the totalweight of resin solids. When used as a combination of the acrylicpolymer and polyester, the binder component includes in the range offrom 1 percent to 99 percent, preferably in the range of from 1 percentto 70 percent and more preferably in the range of from 1 percent to 50percent of the polyester, all percentages being in weight percentagebased on the total weight of the combination.

The acrylic polymer has a GPC weight average molecular weight in therange of from 1000 to 50,000, preferably in the range of from 1000 to20,000 and more preferably in the range of from 5000 to 15,000. Theacrylic polymer has a glass transition temperature (Tg) in the range offrom −80° C. to 150° C., preferably in the range of from −60° C. to 100°C. and more preferably in the range of from −10° C. to 70° C.

The acrylic polymer has a weight average molecular weight of at leastabout 1000, as determined by gel permeation chromatography using apolystyrene standard. Typically the weight average molecular weightranges from about 1000 to about 50,000, preferably from about 2000 toabout 30,000 and more preferably from about 5000 to about 15,000. Theacetoacetate containing polyester has an acetoacetate equivalent weightfrom about 100 to about 2000 (grams/equivalents), preferably from about200 to about 1500 and more preferably from about 300 to about 1000.

Examples of suitable acetoacetate groups-containing acrylic polymersthat may be used according to the invention include addition polymers, 4to 100% by weight of which consists of an acetoacetic ester of ahydroxyalkyl (meth)acrylate or allyl alcohol monomer unit, 0.001% to 96%by weight of an acrylic or methacrylic ester of a mono-, di- orpolyfunctional hydroxyl compound having 1 to 18 carbon atoms, 0.001% to20% by weight of a monoethylenically unsaturated mono- or dicarboxylicacid having 3 to 12 carbon atoms or an anhydride thereof, and 0.001% to96% by weight of one or more other copolymerizable monomers, such asstyrene, α-methyl styrene, vinyl toluene, acrylamide, methacrylamide,acrylonitrile, N-methylol methylol acrylamide, dimethyl maleinate, vinylacetate, vinyl versatate, vinyl trimethoxy silane and/or allyl glycidylether. Suitable monomer units having one or more acetoacetate groupsinclude compounds of the general formula:

H₂C═CHR₁—C(O)—X—R₂—[O—C(O)—CH₂—C(O)—CH₃]_(n−1)

where the group R₁ represents a hydrogen atom or a methyl group, thegroup X an oxygen atom or an NH-group and the group R₂ is ann-functional organic group having 1 to 26 carbon atoms and n is a numberof 2 to 4; the molecular weight of such a monomer unit is generally nothigher than 500, preferably 140 to 300. The n-functional organic groupR₂ may contain urethane groups, ether groups and/or ester groups, forexample obtained from a lactone, such as ε-caprolactone, or an epoxycompound or isocyanate compound such as an alkylene oxide, glycidol, aglycidyl ester of a monocarboxylic acid containing 2 to 18 carbon atomsor an adduct of a diisocyanate and a diol. These monomer units areobtained for instance by acetoacetylation of an adduct of a lactone, amonoepoxy compound or a diisocyanate reacted with a diol to ahydroxyallyl (meth)acrylate. Examples of other suitable monomer unitsinclude allyl acetoacetate and acetoacetic esters of ethylenicallyunsaturated diols or triols such as 2-butene-1,4-diacetoacetate and(2-methylene acetoacetyl)-1-propene-3-acetoacetate.

Examples of suitable acrylic or methacrylic esters of a mono-, di- orpolyfunctional hydroxyl compound include methyl acrylate, methylmethacrylate, ethyl acrylate, hydroxyethyl acrylate, hydroxyethylmethacrylate, propyl acrylate, hydroxypropyl methacrylate, butylacrylate, butyl methacrylate, hydroxyhexyl acrylate, 2-ethylhexylacrylate, octyl acrylate, isobomyl acrylate, oleyl acrylate, glycidylmethacrylate or (meth)acryloxypropyl trimethoxysilane.

Examples of suitable monoethylenically unsaturated mono- or dicarboxylicacids containing 3 to 12 carbon atoms or an anhydride thereof areacrylic acid, methacrylic acid, maleic acid, itaconic acid, maleicanhydride, cinnamic acid or dodecenic acid.

The acrylic polymers may be prepared in any convenient manner, forinstance by polymerizing one or more acetoacetate groups containingmonomer, optionally mixed with one or more other monomers, at atemperature of 50° C. to 160° C., in the presence of preferably 0.1 to10% by weight of an initiator, calculated on the monomeric compound(s).Examples of suitable initiators include free radical initiators, forinstance potassium persulphate, hydrogen peroxide, cumene hydroperoxide,benyoyl peroxide, ditert. butyl peroxide, tert. butylpertrimethylhexanoate, tert. butyl perbenzoate, azobisisobutyronitrile,azobisvaleronitrile, azobis(2,4-dimethylvaleronitrile). Thepolymerization is carried out in the presence of water and/or an organicsolvent, such as a ketone, an alcohol, an ether, an ester or ahydrocarbon. The polymerization may optionally be carried out by usingUV light and in the presence of UV initiators, such as benzil, benzoinethers and thioxanthone derivatives.

Other suitable acetoacetate groups-containing acrylic polymers areaddition polymers having, for instance, hydroxyl groups, a number ofwhich have been converted with an acetoacetate compound or a compoundyielding acetoacetate groups, such as for instance with diketene.Examples of suitable acetoacetate compounds include alkyl esters ofacetylacetic acid, preferably methyl acetoacetate or ethyl acetoacetate.Suitable hydroxyl groups-containing addition polymers include copolymersof a hydroxyalkyl (meth)acrylate such as hydroxyethyl methacrylate,hydroxypropyl methacrylate and/or hydroxybutyl acrylate and optionallyone or more other comonomers, and copolymers of styrene and allylalcohol.

The acetoacetate containing polyester suitable for use in the presentinvention has a weight average molecular weight of at least about 1000,as determined by gel permeation chromatography using a polystyrenestandard. Typically the weight average molecular weight ranges fromabout 1000 to about 50,000, preferably from about 2000 to about 30,000and more preferably from about 1000 to about 15,000. The acetoacetatecontaining polyester has an acetoacetate equivalent weight from about100 to about 2000 (grams/equivalents), preferably from about 200 toabout 1500 and more preferably from about 300 to about 1000.

The acetoacetate containing polyester is prepared as thetransesterification reaction product of a polyester polyol and anacetoacetate containing material. The polyester polyol can be preparedby esterification of an organic polycarboxylic acid or anhydride thereofwith organic polyol and/or an epoxide. Usually, the polycarboxylic acidor anhydride is an aliphatic or aromatic dibasic acid or acid anhydrideand the polyol is a diol.

Examples of diols which are usually employed in preparing the polyesterpolyol include alkylene glycols, such as ethylene glycol, neopentylglycol and other glycols, such as cyclohexane diol, bisphenol-A,hydrogenated bisphenol-A, cyclohexanedimethanol, the reaction productsof lactones and diols, for example, the reaction product ofc-caprolactone and ethylene glycol, hydroxy-alkylated bisphenols, andpolyether glycols, for example, poly(oxytetramethylene)glycol.

The acid component of the polyester polyol consists primarily ofmonomeric carboxylic acids or anhydrides having 2 to 18 carbon atoms permolecule. Among the acids which are useful are phthalic acid,isophthalic acid, terephthalic acid, tetrahydrophthalic acid,hexahydrophthalic acid, methylhexahydrophthalic acid, adipic acid,azelaic acid, sebacic acid, maleic acid, glutaric acid, chlorendic acidand tetrachloophthalic acid. Higher polycarboxylic acids, such astrimellitic acid and tricarballylic acid may also be employed.

Suitable polyesters include polyurethane polyols produced by reactingorganic polyisocyanates with polyester polyols such as those describedabove. The organic polyisocyanate is reacted with the polyol so that theOH/NCO equivalent ratio is greater than 1:1 such that there areresultant free hydroxyl groups and an isocyanate equivalent weightapproaching 1,000,000. The organic polyisocyanate which is used inpreparing the polyurethane polyols can be of varying types but usuallyis an aliphatic or aromatic polyisocyanate or a mixture thereof is wellsuited. Diisocyanates are preferred, although higher polyisocyanatessuch as triisocyanates can be used. Examples of suitable diisocyanatesare 4,4′-diphenylmethane diisocyanate, 1,4-tetramethylene diisocyanate,isophorone diisocyanate and 4,4′-methylenebis(cyclohexyl isocyanate).Examples of suitable higher functionality polyisocyanates arepolymethylene polyphenyl isocyanates.

The coating composition of the present invention, which is formulatedinto high solids coating systems further contains at least one organicsolvent typically selected from the group consisting of aromatichydrocarbons, such as petroleum naphtha or xylenes; ketones, such asmethyl amyl ketone, methyl isobutyl ketone, methyl ethyl ketone oracetone; esters, such as butyl acetate or hexyl acetate; and glycolether esters, such as propylene glycol monomethyl ether acetate. Theamount of organic solvent added depends upon the desired solids level aswell as the desired amount of VOC of the composition. If desired, theorganic solvent may be added to both components of the binder. Theamount of organic solvent used in the present invention results in thecomposition having a VOC of less than 0.6 kilogram (5 pounds per gallon)and preferably in the range of 0.012 kilogram to 0.528 kilogram (0.1pounds to 4.4 pounds per gallon), more preferably in the range of from0.12 kilogram to 0.42 kilogram (1.0 to 3.5 pounds per gallon) of organicsolvent per liter of the composition. The solids level of the coating ofthe present invention varies in the range of from 5 percent to 100percent, preferably in the range of from 10 percent to 95 percent andmore, preferably in the range of from 25 percent to 85 percent, allpercentages being based on the total weight of the coating composition.

The coating composition of the present invention may also containconventional additives, such as pigments, stabilizers, rheology controlagents, flow agents, toughening agents and fillers. Such additionaladditives will, of course, depend on the intended use of the coatingcomposition. Fillers, pigments, and other additives that would adverselyeffect the clarity of the cured coating will not be included if thecomposition is intended to be used as a clear coating. The foregoingadditives may be added to either the binder or crosslinking component,or both, depending upon the intended use of the coating composition.

In use, the binder and crosslinking components of the coatingcomposition are mixed just prior to use or about 5 to 30 minutes beforeuse to form a pot mix, which has limited pot life, in the range of from10 minutes to 60 minutes, before it becomes too viscous to permitapplication through conventional application systems, such as spraying.A layer of the pot mix is typically applied to a substrate byconventional techniques, such as spraying, electrostatic spraying,roller coating, dipping or brushing. The layer of the coatingcomposition then cures under ambient conditions in the range of 10minutes to 3 hours, preferably in the range of 30 minutes to 60 minutesto form a coating on the substrate having the desired coatingproperties. It is understood that the actual curing time depends uponthe thickness of the applied layer and in the presence or absence of anysuitable drying devices, such as fans that assist in continuouslyflowing air over the coated substrate to accelerate the cure rate.Generally, a layer having a thickness in the range of from 25micrometers to 300 micrometers applied over a metal substrate, such asautomotive body, cures in 30 to 60 minutes under ambient conditions andin the absence of any suitable drying devices. If desired, baking thecoated substrate at a temperature of about 60° C. for about 30 minutesmay further accelerate the cure rate. The foregoing baking step isparticularly useful under OEM (Original Equipment Manufacture)conditions.

Testing Procedures

The following test procedures were used for generating data reported inthe examples below:

Cure Rate Test

A layer having a dry coating thickness in the range of 58 micrometers to68 micrometers from a coating composition (at 50% solids level) wasapplied over a steel panel using a doctor blade and the cure rate of thelayer was measured. The change in film hardness of the test layers wasmeasured with respect to time by using a-Persoz hardness tester ModelNo. 5854 (ASTM D4366), supplied by Byk-Mallinckrodt, Wallingford, Conn.The number of oscillations (referred to as Persoz number) were recordedafter 3 hours. The larger the Persoz number, the harder the film willbe, thereby demonstrating a faster cure rate of the layer. For thepurpose of this invention, a Persoz number of about 80 to 100 after 3hours dry time for a coating composition is considered acceptable. APersoz number of about 60 or less is considered not acceptable, since acoating from a primer made therefrom could not be aggressively sandedwithout fouling the sandpaper after an hour of ambient cure.

Viscosity Measurement

The viscosity of the pot mix of the coating compositions was measured byusing the conventional Zahn #2 cup supplied by VWR Scientific ProductsCorporation. The viscosity was measured as soon as the pot mix wasprepared and then 30 minutes thereafter. The reading was recorded asnumber of seconds it took for the pot mix to drain from the Zahn #2 cup[ASTM D1084 (Method D)]. The lower the Zahn number, the lower is theviscosity of the pot mix. For the purpose of this invention, the Zahnnumber of about 45 at 30 minute intervals is considered acceptable andthe Zahn number of greater than 55 for the same time interval isconsidered not acceptable.

The invention is illustrated in the following Examples:

EXAMPLES Structured Reactive Diluent of Example A

Synthesis of Pentaerythritol Tetraacetoacetate (PE/AcAc)

To a glass reactor equipped with a thermometer, stirrer, nitrogenblanket, Vigreux column, condenser, distillation adapter and receiver,Charge-I, shown below was added. The reaction mixture was heated toboiling and 217.6 parts of tert-butyl alcohol were removed byatmospheric distillation (the maximum batch temperature was 180° C.).The acid number of the reaction rnire was less than 5. The batch wasthen cooled to room temperature to give the acetoacetate functionalpentaeryiritol as a clear liquid. Gardner-Holdt viscosity=L at 95%solids. Glass transition temperature=−45° C. Analysis of the product bymass spectroscopy (electronspray) indicated a molecular weight equal to472 g/mol.

Ingredients-Charge-I Parts by Weight (grams) Pentaerythritol 100Tert-butylacetoacetate 464.7 Total 564.7

Structured Reactive Diluent of Example B

Structured Tetraacetoacetate Oligomer (PE/MHHPA/Cardura E-10/AcAc)

To a 5-liter flask fitted with an agitator, condenser, heating mantle,nitrogen inlet, thermocouple and an addition port Charge-I, shown below,was added. The mixture was then heated to 140° C. and held for 1 hour.Charge-II, shown below, was then added over a period of 1 hour and helduntil the acid number of the reaction mixture was less than 2.Charge-III, shown below, was then added and 296 g t-butyl alcohol wasremoved by distillation. The acid number of the reaction mixture wasless than 5. Finally, Charge-IV, shown below, was added and the reactionmixture was stirred for 1 hour and then cooled to room temperature togive a clear solution. Gardner-Holdt viscosity=t+1/2 at 80.5% solids.

Ingredients Parts by Weight (grams) Charge-I Pentaerythritol 136.0Methylhexahydrophthalic anhydride 672.0 Triethylamine 9.0 Charge-IIEpoxide¹ 1010 Charge-III Tert-butylacetoacetate 633 Charge-IV2-Heptanone 455 Total 2915.0 ¹Cardura ® E-10 is a glycidyl ester of C-10acid and is available from Shell Chemical Company.

Structured Reactive Diluent of Example C

Structured Tetraacetoacetate Polyester Oligomer (PE/MHHPA/EO/AcAc)

To a vessel rated for high pressure Charge-I, shown below, was added andthe batch was heated to 140° C. Charge-II, shown below, was then addedover a one hour interval, followed by continued heating for 6 hours. Thebatch was cooled to 25° C. and Charge III, shown below, was added, andfollowed by heating at 110° C. for 6 hours. Residual ethylene oxide wasremoved by purging with nitrogen. The acid number on solids was testedat less than 10 mg KOH/gram. Charge-IV, shown below, was added and thebatch was heated to 120° C. and 296 g tert-butylalcohol were removedthereafter during distillation. The acid number of the reaction mixturewas less than 5. The mixture cooled to room temperature was a clearsolution. Gardner-Holdt viscosity=V+1/2 at 82.7% solids.

Ingredients Parts by Weight (grams) Charge-I 2-Heptanone 303Pentaerythritol 136 Triethylamine 0.23 Charge-II Methylhexahydrophthalicanhydride¹ 654 Charge-III Ethylene oxide 176 Charge-IVTert-butylacetoacetate (TBAA) 632 Total 1901.23 ¹Milldride ®Methylhexahydrophthalic anhydride supplied by Milliken Chemical Company.

Structured Reactive Diluent of Example D

Hyperbranched Polyester Functionalized with Acetoacetate

To a 2 liter three-neck flask equipped with a mechanical stirrer,thermocouple, short path distillation head with a water condenser undernitrogen flow was placed dimethylolpropionic acid (DMPA, 200 g, 1.49mole), e-caprolactone (400 g, 3.51 mole),4,4′-isopropylidenedicyclohexanol (179 g, 0.74 mole), tin(II)di(2-ethylhexanoate) (Sn(O₂CC₇H₁₅)₂, 3 g, 0.0074 mole), xylenes (20 ml)and heated at 180° C. The reaction progress was monitored by the acidnumber measurements and by the water volume collected. After 4 hours, 18ml water was collected, 1 g sample was withdrawn, dissolved in 10 mlDMSO and the acid number (30.6) was determined by titration with 0.1 NKOH in MeOH. The reaction was stopped (heat off) after a total of 10hours, when the acid number was 1.1 and 23.5 ml water was collected. Thepolymer had viscosity=5.7 poise for a 90 weight percent solution inbutyl acetate at room temperature. Charge-II was added and the mixturewas heated to 90° C. during which time tert-butanol was removed bydistillation. After the theoretical amount of tert-butanol wascollected, the mixture was cooled to room temperature. Unreactedtert-butyl acetoacetate and propylene glycol methyl ether acetate(solvent) was removed by distillation in vacuum, giving the product asviscous oil. Analysis of the product by infrared spectroscopy indicatedthat the hydroxyl to acetoacetate functional group conversion was inexcess of 90%.

Ingredients Parts by Weight (grams) Charge-I Dimethylolpropionic acid200 ε-caprolactone 400 4,4′-isopropylidenedicyclohexanol 179 tin(II)di(2-ethylhexanoate) 3 Xylenes 20 ml Charge-II Propylene glycolmethylether acetate 1129 Tert-butylacetoacetate (TBAA) 520 Total 2451

Structured Reactive Diluent of Example E

(β-Cyclodextrin-Acetoacetate)

To a 500-mL flask equipped with a mechanical stirrer, heating mantle anddistillation head with a water-cooled condenser was added to charge I.The contents were warmed to 70° C. giving a homogeneous solution. ChargeII was then added and the contents of the flask were heated to 85° C. to90° C. during which time tert-butanol was slowly distilled from thereaction mixture. After collecting 32 g tert-butanol, the mixture wascooled to 30° C. to 40° C. Unreacted tert-butyl acetoacetate and N,Ndimethylacetamide were removed by distillation in vacuo, affording aviscous, dark orange oil. Analysis of the product by mass spectroscopy(electronspray) indicated the presence of a distribution of productswith a total of 15 to 21 hydroxyl groups on the cyclodextrin ring (outof a maximum of 21) converted to the acetoacetate group.

Ingredients Parts by Weight (grams) Charge-I β-cyclodextrin 30N,N-dimethylacetamide 281.1 Charge-II Tert-butylacetoacetate 180 Total491.1

Example F (Acetoacetate Functional Acrylic Polymer)

To a reactor, Charge-I, shown below, was added and the batch was heatedto boiling (125° C.) under nitrogen atmosphere. Thereafter, Charge-II,shown below, was added over a period of 210 minutes and startingsimultaneously Charge-III, shown below, was added over a period of 270minutes. The reaction mixture was then held for an additional 60 minutesat boiling after the feeds had been completed. After the hold period,Charge-IV, shown below, was added and the reaction mixture was cooleddown to room temperature to produce a clear solution. Gardner-Holdtviscosity=D at 50% solids.

Ingredients Parts by Weight (grams) Charge-I Butyl acetate 273.34Charge-II Styrene 160.92 Acetoacetoxyethyl methacrylate 201.1Hydroxyethyl acrylate 40.2 Butyl acetate 27 Charge-III t-butylperoxyacetate 21.5 (75% solution in mineral spirits) Butyl acetate 71.87Charge-IV Butyl acetate 30 Total 825.93

Example G (Acetoacetate Functional Polyester)

To a 5-liter reactor equipped with 10″ packed separation column, waterseparator and condenser, Charge-I, shown below, was added while beingpurged with nitrogen. The reaction batch was gradually heated over 9.5hours to 230° C., while distilling off 356 g of water from the reactionmixture. The reaction temperature was then reduced to 75° C. andCharge-II, shown below, was added. The reaction temperature was thengradually increased to 140° C. with stirring over s a period of 3 hourswhile removing 404 g tert-butyl alcohol liquid by distillation. The acidnumber of the reaction mixture was less than 5. The reaction mixture wasthen cooled to room temperature to produce a clear solution.Gardner-Holdt viscosity=Y+1/2 at 73.8% solids.

Ingredients Parts by Weight (grams) Charge-I Neopentyl glycol 946.1Trimethylol propane 270.4 Isophthalic acid 787.1 o-Phthalic anhydride701.75 Monobutyl tin oxide¹ 0.7 water 100 Toluene 83.68 Charge-II Xylene966.32 TBAA 817.24 Total 4673.29 ¹FASCAT ® 4100 Monobutyl tin oxidesupplied by Elf Atochem.

Examples of Coating Compositions

Coatings from all the examples of coating compositions were applied at50% solids solutions by weight on cold roll steel panels using a doctorblade to achieve uniform film thickness. Film thickness after drying wasin the range 58 to 68 micrometers. Zahn #2 viscosity values forsolutions of the coating mixtures were measured at time zero and 30minutes. Persoz hardness values for the coatings were measured afterdrying for 3 hours. Comparative examples, shown in Table 1 below, andexamples of the present invention, shown in Table 2 below, were preparedby successively mixing of the components shown in Tables 1 and 2 below(All components are in parts by weight):

Comparative Comparative Components Example 1 Example 2 Example F(Polyacrylic) 84.0 — Example G (Polyester) — 20.3 Pentaerythritol — —tetraacrylate —  4.9 Ketimine* 42.2 42.2 Solvent**  3.7 19.7Measurements Zahn #2 (T = 0s) 30s 24s Zahn #2(T = 30 min) gel 27s Persoz(3h) 53 24 *Prepared from 1 mole of Epon ® 828 epoxide and 2 molesepichlorohydrin **Butyl acetate

Components Ex. 1**** Ex. 2 Ex. 3 Ex. 4 Ex. 5 Example F 16.1 g 16.1 g16.1 g 59.4 g 16.1 g Example A 6.8 g — — — — Example B — 37.4 g — — —Example C — — 22.4g — — Example D — — — 22.8 g — Example E — — — — 13.3gKetimine* 42.2 g 42.2 g 42.2 g 42.2 g 42.2 g Solvent 10.4** 4.2** 18.3**17.5** 17.5*** Measurements Zahn #2 (T = 0s) 20s 17s 18s 30s 24s Zahn #2(T = 30 26s 21s 25s 42s 41s min) Persoz (3h) 120 96 73 64 81 *preparedfrom 1 mole diglycidyl ether of Bisphenol A and two moles of thediketimine of dipropylene triamine and methylisobutyl ketone. **Butylacetate ***Acetone ****Ex. means Example

From Tables 1 and 2 it is seen that by utilizing structured reactivediluents in the coating compositions, unexpectedly significantly fasterdrying rates, as signified by the Persoz values, are observed. SeeExamples 1 through 5 in Table 2 as compared to low drying rates observedin Comparative Examples 1 and 2 in Table 1. Furthermore, what is stilleven more unexpected is Examples 1 through 5 in Table 2 provide fasterdrying rates than Comparative Examples with no significant rise in theviscosities of the pot mixes made therefrom.

What is claimed is:
 1. A coating composition comprising: a crosslinkingcomponent comprising a polyamine, a polyketimine, or a combinationthereof, wherein said polyamine has an average of at least two aminefunctionalities per polyamine molecule and wherein said polyketimine hasan average of at least two ketimine functionalities per polyketiminemolecule; and a binder component comprising: at least one structuredreactive diluent having a GPC weight average molecular weight in therange of from 100 to 45,000, said diluent being substantially free fromacrylate functionalities and having at least two acetoacetatefunctionalities per diluent molecule; and a binder polymer, whichcomprises an acrylic polymer, a polyester, or a combination thereofwherein said acrylic polymer or said polyester is functionalized withacetoacetate functionalities.
 2. The coating composition of claim 1wherein said binder polymer has a GPC weight average molecular weight inthe range of from 1000 to 50,000.
 3. The coating composition of claim 1wherein said reactive diluent is further provided with at least twocycloaliphatic functionalities.
 4. The coating composition of claim 1wherein said structured reactive diluent comprises in the range of 2 to30 of said acetoacetate functionalities per said diluent molecule. 5.The coating composition of claim 1 wherein said diluent is a reactionproduct of an acetoacetate compound with a structured polyol.
 6. Thecoating composition of claim 5 wherein said structured polyol is a starshaped polyol having 3 to 10 arms.
 7. The coating composition of claim 6wherein said star shaped polyol is expanded by reaction with ananhydride or an acid anhydride.
 8. The coating composition of claim 1wherein said diluent is a reaction product of an acetoacetate compoundwith a dendritic oligomers or polymers.
 9. The coating composition ofclaim 1 wherein said diluent is a reaction product of an acetoacetatecompound with a cyclodextrin.
 10. The coating composition of claim 1wherein said polyamine or polyketimine has a GPC weight averagemolecular weight in the range of from 100 to 50,000.
 11. The coatingcomposition of claim 1 wherein said composition comprises in the rangeof from 25 to 75 percent of said crosslinking component, saidpercentages being in weight percentages based on the total weight ofcrosslinking and binder components solids.
 12. The coating compositionof claim 1 wherein said composition comprises in the range of from 1 to60 percent of said reactive diluent, said percentages being in weightpercentages based on the total weight of crosslinking and bindercomponents solids.
 13. The coating composition of claim 1 wherein saidcomposition comprises in the range of from 20 to 80 percent of saidbinder polymer, said percentages being in weight percentages based onthe total weight of crosslinking and binder components solids.
 14. Thecoating composition of claim 1 wherein a volatile organic componentcontent of said composition is in the range of 0.012 kilograms to 0.528kilograms per liter (0.1 pounds to 4.4 pounds per gallon) of saidcomposition.
 15. A method of producing a coating on a substrate, saidmethod comprising: mixing a crosslinking component with a bindercomponent to form a pot mix, said crosslinking component comprising apolyamine, a polyketimine, or a combination thereof, said polyaminehaving an average of at least two amine functionalities per polyaminemolecule and said polyketimine having an average of at least twoketimine functionalities per polyketimine molecule; said bindercomponent comprising at least one structured reactive diluent having aGPC weight average molecular weight in the range of from 100 to 45,000,said diluent being substantially free from acrylate functionalities andhaving at least two acetoacetate functionalities per said diluentmolecule; and a binder polymer, which comprises an acrylic polymer, apolyester, or a combination thereof wherein said acrylic polymer or saidpolyester is functionalized with acetoacetate functionalities; applyinga layer of said pot mix on surface of said substrate; and curing saidlayer under ambient conditions to form said coating on said surface ofsaid substrate.
 16. The method of claim 15 wherein said layer has athickness in the range of from 25 micrometers to 300 micrometers. 17.The method of claim 16 wherein said layer cures in the range of from 5minutes to 120 minutes from the said application of said layer on saidsurface.
 18. The method of claim 15 wherein said surface is anautomotive body.
 19. A coating composition comprising: a crosslinkingcomponent comprising a polyamine, a polyketimine, or a combinationthereof, wherein said polyamine has an average of at least two aminefunctionalities per polyamine molecule and wherein said polyketimine hasan average of at least two ketimine functionalities per polyketiminemolecule; and a binder component comprising: at least one structuredreactive diluent having a GPC weight average molecular weight in therange of from 100 to 45,000, said diluent being substantially free fromacrylate functionalities, having at least two acetoacetatefunctionalities per diluent molecule and wherein said structuredreactive diluent is a reaction product of an acetoacetate compound with:a structured polyol, dendritic oligomers or polymers, or a cyclodextrin.20. A method of producing a coating on a substrate, said methodcomprising: mixing a crosslinking component with a binder component toform a pot mix, said crosslinking component comprising a polyamine, apolyketimine, or a combination thereof, said polyamine having an averageof at least two amine functionalities per polyamine molecule and saidpolyketimine having an average of at least two ketimine functionalitiesper polyketimine molecule; said binder component comprising at least onestructured reactive diluent which: has a GPC weight average molecularweight in the range of from 100 to 45,000, is substantially free fromacrylate functionalities, has at least two acetoacetate functionalitiesper said diluent molecule; and is a reaction product of an acetoacetatecompound with: a structured polyol, dendritic oligomers or polymers, ora cyclodextrin; applying a layer of said pot mix on surface of saidsubstrate; and curing said layer under ambient conditions to form saidcoating on said surface of said substrate.